comcast activation crap

at someone's place, this new modem given out by comcast is forcing to activate, requiring to enter account number. It is wall-guard or wallguard, some nonsense. The rudimentary workaround: enter dns server ip's manually and connect, since wall-guard is sitting between comcast dhcp server and your modem. Upon some investigation, I found out that the SHIT that controls wall-guard (a config file) resides on your cable modem. Next step, then, is: why not flash that modem with some hackware, the way one can flash a netgear/linksys router with tomato. There is a way to get around comcast trickery of throttling, etc